2 * (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
3 * See the copyright notice in the ACK home directory, in the file "Copyright".
5 * Author: Ceriel J.H. Jacobs
7 /* $Id: exp.c,v 1.6 1994/06/24 11:43:26 ceriel Exp $ */
12 #include "localmath.h"
18 /* Algorithm and coefficients from:
19 "Software manual for the elementary functions"
20 by W.J. Cody and W. Waite, Prentice-Hall, 1980
24 0.25000000000000000000e+0,
25 0.75753180159422776666e-2,
26 0.31555192765684646356e-4
30 0.50000000000000000000e+0,
31 0.56817302698551221787e-1,
32 0.63121894374398503557e-3,
33 0.75104028399870046114e-6
54 /* ??? avoid underflow ??? */
56 n = x * M_LOG2E + 0.5; /* 1/ln(2) = log2(e), 0.5 added for rounding */
62 g = ((x1-xn*0.693359375)+x2) - xn*(-2.1219444005469058277e-4);
69 x = g * POLYNOM2(xn, p);
71 return (ldexp(0.5 + x/(POLYNOM3(xn, q) - x), n));